The present invention is directed generally to a high torque cushioned drive coupling and more specifically to a drive coupling particularly adapted for connecting the drive shafts on a center pivot irrigation tower to the worm gearbox which drives them.
Center pivot irrigation system towers are commonly constructed with a worm gearbox for intermittently driving the support wheels of that tower for advancing a respective section of the water pipe around the center pivot. Because each tower may start and stop every one or two minutes, a rigid coupling is unacceptable because of the repeated shock that would be delivered to the system generally. Accordingly, cushioned drive couplings have been devised wherein a body of rubber or the like is interposed between abutting portions of the coupling to absorb impact from starts and stops.
Known cushioned couplings have several undesirable limitations, however. Some include many parts when in disassembled form, thereby substantially complicating installation and storage of the replacement couplings. More significant is the short service life of known cushioned couplings. Because these couplings are installed adjacent the irrigation tower ground wheels and because they are often exposed to mud and dirt during operation, foreign matter such as sand and dirt tends to enter the cracks between the rubber insert and metal coupling sections and wear out the rubber insert. If a harder rubber is used to resist wear, its cushioning function is comprised. Finally, unitary couplings which slide-fit onto the drive shafts often rust onto the shaft making removal very difficult. An alternate problem of such couplings is that if they become loose, the coupled end of the drive shaft can be worn out.
Accordingly, a primary object of the invention is to provide an improved high torque cushion drive coupling.
Another object is to provide such a coupling having a resilient insert resistant to entry of foreign matter between the insert and adjacent coupling portions.
Another object is to provide such a coupling which can be easily installed onto and removed from a pair of shafts to be coupled.
Another object is to provide such a coupling in the form of two identical half sections adapted to be clamped onto opposite sides of the shafts to be coupled.
Another object is to provide a high torque cushion drive coupling which is simple and rugged in construction, economical to manufacture and efficient in operation.